DELL PC6224F User Manual

OSPFv3 Commands

Graceful restart is disabled by default

Router OSPFv3 Configuration mode

Graceful restart works in concert with nonstop forwarding to enable the 

hardware to continue forwarding IPv6 packets using OSPFv3 routes while a 

backup unit takes over management unit responsibility. When OSPF 

executes a graceful restart, it informs its neighbors that the OSPF control 

plane is restarting, but that it will be back shortly. Helpful neighbors continue 

to advertise to the rest of the network that they have full adjacencies with the 

restarting router, avoiding announcement of a topology change and 

everything that goes with that (i.e., flooding of LSAs, SPF runs). Helpful 

neighbors continue to forward packets through the restarting router. The 

restarting router relearns the network topology from its helpful neighbors. 
This implementation of graceful restart restarting router behavior is only 

useful with a router stack. Graceful restart does not work on a standalone, 

single-unit router.

–

Use the nsf-helper to allow OSPF to act as a helpful neighbor for a restarting 

router.  Use the “no” form of this command to prevent OSPF from acting as a 

helpful neighbor.

nsf helper[ planned-only ]
no nsf helper

• planned-only

 — This keyword indicates that OSPF should only help a 

restarting router performing a planned restart.